The PNG file format is opened by special programs. To open given format, download one of the suggested programs.
How to open a PNG file
The PNG extension is a file format used to store images without quality loss. It is the most popular photo format on the Internet, specially designed for use on the Web.
What's in PNG files
A file with the PNG file extension is a file Portable Network Graphics. The format uses lossless compression and is generally seen as an alternative to GIF. But unlike , PNG files do not support animation.
Both grayscale and full color photos have PNG format, transparent layers are supported. PNG compression usually better than that, which is used in GIF. JPG sometimes has more advantages over PNG, but after such compression, defects can occur in images with text or around high contrast areas.
How to open a PNG file
To open PNG files, you can use any Internet browser or graphics editor. Both the Windows OS platform and Mac OS have built-in mechanisms for viewing such images. Program Png- The default Windows Photo Viewer is often used to open PNG files because it system program Windows. But there are many other ways to view them.
All browsers (ex. chrome, firefox, Internet Explorer etc.) will automatically view the PNG files you open online, meaning you don't have to download every PNG file you want to view on your computer. You can also use the browser to open PNG files already on your computer with the combination Ctrl keys+ O. Most of these programs also support drag-and-drop, so you can simply drag and drop a PNG file into your browser to open it.
PNG conversion
Image files can be converted different ways, for example, convert to png and from it using various programs and online services. For example, the Png editor - Photo Converter allows you to do this.
Image file stored in the Portable Network Graphic (PNG) format; Contains a bitmap of colors and uses lossless compression close to a file, but without copying restrictions. Typically used to store web image graphics.
The PNG (pronounced PNG) format was created in response to format limitations, primarily to increase color support and provide a patent-free image format. In addition to this, while the files
Good day!
Have you ever wanted to know how PNG files work? Not? But I'll tell you anyway.
The PNG (Portable Network Graphics) format was invented in 1995 to replace GIF, and already in 1996, with the release of version 1.0, it was recommended by the W3C as a full-fledged network format. PNG is one of the main web graphics formats today.
Under the cut you will find general description PNG file structures, a number of diagram pictures, preparation in a hex editor, and, of course, a link to the specification.
General structure
The PNG structure in its most general form is shown in the following figure.
That is, the file consists of a signature and a certain number of blocks (chunks, chunks), each of which carries some information (thanks to KO!). But why can't the signature be considered one of the chunks? Let's take a closer look.
File signature
The signature of a PNG file is always the same, consists of 8 bytes, and represents (in hex notation)What does this mean?
- 89 is a non-ASCII character. Prevents PNG from being recognized like text file, and vice versa.
- 50 4E 47 - PNG to ASCII notation.
- 0D 0A - CRLF (Carriage-return, Line-feed), DOS-style line feed.
- 1A - stops file output in DOS mode (end-of-file) so that you do not get a multi-kilobyte image in text form.
- 0A - LF, Unix-style newline.
Chunks
Chunks are blocks of data that make up a file. Each chunk consists of 4 sections.
Let's take these sections in order.
Length
Well, everything seems to be clear with the length. Just a numeric value for the length of the data block.Type (name)
With the type a little more interesting. The type is 4 case sensitive ASCII characters. The registers of characters (the fifth bit in the numeric notation of the character) in the chunk name differ for a reason - these are flags that tell the decoder some additional information.- The case of the first character determines whether the given chunk is critical( uppercase) or auxiliary (lower case). Critical chunks must be recognized by every decoder. If a decoder encounters a critical chunk whose type it cannot recognize, it must fail.
- The case of the second character specifies whether the chunk is "public" (upper case) or "private" (lower case). "Public" chunks - official, documented, recognized by most decoders. But if suddenly you need to encode specific information for some of your needs, then just make the second character small in the name of the chunk.
- The case of the third character is left for future accomplishments. It is intended to be used to differentiate between different versions of the standard. For versions 1.0 and 1.1, the third character must be large. If it (suddenly!) turns out to be small, all current decoders should treat the chunk as they would any other unrecognized one (that is, exit with an error if the chunk is critical, or skip otherwise).
- The case of the fourth character means that this chunk can be copied by editors who cannot recognize it. If the case is lower case, the chunk can be copied regardless of how much the file has been modified, otherwise (upper case) it is copied only if no critical chunks were affected by the modification.
Below is a list of chunk types with brief explanations.
Critical Chunks
- IHDR- file header, contains basic information about the image. Must be the first chunk.
- PLTE- palette, list of colors.
- IDAT- contains, actually, the image. A drawing can be split into multiple IDAT chunks for streaming. Each file must have at least one IDAT chunk.
- IEND- the final chunk, must be the last one in the file.
Auxiliary Chunks
- bKGD- this chunk sets the main background color.
- CHRM used to set the CIE 1931 color space.
- gAMA- determines the gamma.
- hIST- this chunk can store a histogram or the total content of each color in the image.
- iCCP - color profile ICC
- iTXt- contains text in UTF-8, possibly compressed, with an optional language tag. iTXt chunk with keyword"XML:com.adobe.xmp" may contain Extensible Metadata Platform (XMP) .
- pHYs- contains the estimated pixel size and/or aspect ratio of the image.
- sBIT(significant bits) - determines the "color-accuracy" (color-accuracy) of the image (black and white, full color, black and white with transparency, etc.), for easier decoding.
- sPLT- suggests a palette to use if the full range of colors is not available.
- sRGB- indicates the use of the standard sRGB scheme.
- ster- indicator of stereoscopic images.
- tEXt- may contain text in ISO/IEC 8859-1 format, with one name=value pair for each chunk.
- time- stores the date last change Images.
- tRNS- contains information about transparency.
- zTXt- compressed text, with the same restrictions as tEXt.
CRC
CRC-32 checksum. By the way, the other day there was a topic about its calculation in Windows.Minimum PNG
We have dealt with the general structure. Now let's analyze the content of the required chunks. But which ones are mandatory (not critical, critical must be recognized by the decoder, and not present in each file), and what does the minimum PNG file look like? That's how:
IHDR
The data block in IHDR contains the following fields:- Width, 4 bytes
- Height, 4 bytes
- Bit depth (bit depth), determines the number of bits per sample (not a pixel), 1 byte
- Color type, consists of 3 flags 1 (palette is used), 2 (color is used, not monochrome), and 4 (alpha channel is present), 1 byte
- compression method. On the this moment only value 0 is available - compression by deflate algorithm. If the value is not 0, the chunk is considered unrecognized and the decoder reports an error. 1 byte
- Filtration method. Just as in the case of compression, at the moment it can only be zero. 1 byte
- Interlace (interlacing) method. Specifies the order in which data is transferred. There are currently 2 values available: 0 (no interlace) and 1 (Adam7 interlace). 1 byte
IEND
Signals end of file, data block of this chunk contains nothing.IDAT
Contains data encoded according to the compression method field in the header. The decoding algorithm is beyond the scope of this article (however, if there are those who wish, it may appear in the next one), but it is described quite well (and in Russian).Thus, the simplest PNG file (for example) looks like this. 
Conclusion
When writing this article, I set myself the task of giving the reader general knowledge about the structure of a PNG file; for a deeper understanding, it is recommended to read the specifications.Topic on Habré about the structure of JPEG: habrahabr.ru/blogs/algorithm/102521
Topic on Habré about the structure of GIF: habrahabr.ru/blogs/algorithm/127083
Thank you for your attention, I will be glad to any criticism!
As you know, a popular image resolution is the png format, for editing, on personal computer which exist special programs editors, one of which we will tell you about with the possibility of downloading. Note, for those who do not know, that this format has come to replace the previously popular analogue of gif, which remained in demand, but in a different direction for designers. Interest in the convenient and capacious expansion of images that we are now advertising has been shown by many designers and photographers in our country, as well as in the West, where it is even more appreciated.
In total, for editorial modification of png format pictures, there are a lot of free programs, which you can download for the purpose free use without any restrictions and the need for registration. Well, in order not to be unfounded, I will say that the best editorial program for processing photos and simply images in png format, available for free download, is a product called GIMP, which has a lot of advantages and almost no drawbacks. Of course, if you compare this product with the famous and legendary Photoshop, you can find cons, but not much.
Download png format program to computer
Omitting all the details, I want to say that a program for convenient editing of the png format on a personal computer, which you can download right now and for free, can help you cope with a lot of tasks, regardless of the exacting requirements imposed by the user. One small difficulty in working with the application advertised by me can be its advanced customization, which requires only a little precious time, equal to, in the equivalent of no more than a few minutes. Although, in my opinion, as advanced user, who has worked in this application for more than one month, there is nothing problematic in the user settings made.
The main thing, as I emphasized above, is not to enlist the need to find an alternative to this program for editing the png format, but at the same time and with minimal cost just free of charge and without any restrictions download the distribution kit to your computer with subsequent installation and start using it.
Well, I think from all of the above I can draw a couple of logical conclusions and decide on downloading to your computer or laptop the most convenient editorial program with a lot of advantages and completely absent disadvantages. Well, to go directly to the distribution download itself, you will be helped by paying your close attention to the address mirror links located just below and guaranteeing maximum speed. 06/05/16 27.2K
Sometimes you need to upload an image that contains transparent elements, through which the original background will show through. In these cases, it would be convenient to load PNG images as they are capable of preserving transparency.
In this article, we will tell how to make transparency in photoshop.
File creation
The first step is to create a file. To do this, open Adobe Photoshop and in the File menu ( file) at the top of the page, select "Create" ( New).
Then, in the New Document window that appears ( New document) create a file of the correct size, and make sure the resolution of the document is 72 pixels per inch ( because the file is intended for use on the web). And also that you chose the value "Transparent" ( Transparent) in the Background content drop-down list ( background content).
*Before making a PNG with transparency in Photoshop, we need to clarify that in this example we are creating an image to upload as a background for the site, so the document size is set as follows: width 3000px, height 1730px, which are the recommended sizes for HD image downloads:
After you have set the parameters, click OK to open a new document.
Then in the Layers panel ( Layers) make sure you're working on the transparent layer and not the background:
Once you have completed the creation and are ready to save the transparent image, depending on the version of Photoshop you are using, in the File menu ( file) you can use one of the possible options:
Photoshop versions earlier than CC 2015:
Now we will tell how to make an image transparent in photoshop, which came out before CC 2015 . These versions use the Save for Web method ( Save for Web& Devices) to save and optimize PNG images for use on the web. To use this method, simply go to the File menu ( file), and then - "Save for Web" ( Save for Web & Devices):
Then in the window that pops up select PNG-24 from the drop down menu possible values, and then make sure the Transparency options are selected ( Transparency) and " Convert to sRGB» ( Convert to sRGB). This confirms that the image will contain a transparent background and its color mode will be converted to sRGB , the recommended color space for the web.
Fields " Image size» ( Image Size) are automatically populated with the values you specified when you created the file. But if you want to resize the file before saving, you can do so now.
Photoshop version CC 2015:
Before, how to make photos transparent in photoshop, you need to know that since version CC 2015 the option "Save for Web" ( Save for Web & Devices) in the File menu ( file) is marked Legacy. And replaced by a new option "Export" ( Export) which offers identical functionality with more quick save in file smaller and in best quality. To use the Export option, click the File menu ( file), and then - " Export as» ( export as).
Note: Adobe still offers a Save for Web option ( Save for Web & Devices) in Photoshop CC 2015, and it's available via File > Export ( File > Export) or when using the keyboard shortcut Command+Option+Shift+S (for Mac) or Ctrl+Alt+Shift+S (for PC):
Then, in the window that appears, select PNG from the Format drop-down menu ( Format) and make sure the "Transparency" options are selected ( Transparency) and " Convert to sRGB» ( Convert to sRGB).
Fields " Image size» ( Image Size) and "Canvas Size" ( Canvas Size) should automatically populate with the values you specified when you created the file. However, if you wish, you can change these settings before how to make transparency effect in photoshop.
2 votesGood day, dear readers. Ability to take pictures transparent background incredibly necessary for every novice website developer, designer and even an ordinary person.
This is the most popular function in Photoshop, and therefore I decided to tell you in as much detail as possible not only about the process itself, but also about how to save an image in Photoshop without a background.
It turns out that many have difficulties with this, but there are no publications on the Internet on this topic on the Internet at all. Only a few threads on the forums. But, I take on the mission to correct this injustice ...
So, now I will put on knightly armor and dispel all fears, doubts, misunderstandings and turn the difficulties of Photoshop art into a simple routine. I will also tell you about all the subtleties of craftsmanship. Get ready. “To know” I will be in a very simple language, so that it becomes clear to everyone, so I apologize to readers who are embarrassed by such meticulousness and they themselves know everything very well.
More patient, I thank you for your understanding. Let's get started.
What you need to achieve in order for the photo to be truly transparent
Transparency in the picture is usually displayed like this checker. If you see it on Google, it means that the image can be downloaded without problems and when this object is superimposed on another background, the color will not change.
As you can see, such a checker is not displayed if the image in the search is reflected through the thumbnail. You have to click on the picture and Additional Information will open.
Look, I copied this drawing and pasted it onto the photo of the field. I will not go into exactly how I did it, now it does not matter. The most important thing is that you can see all parts of the field, the cubes seem to have been cut out and superimposed on the picture.
If I had not found a photo with a checker in the search, the illustration would have looked completely different. The background would be white and rectangular.
Why is that? This checker is a common feature, if you see it, then there is no color at all in this part of the illustration, and when superimposed, you will see lower part drawing. Similarly, transparency is displayed and . If you need to remove the background from a photo, then you need to ensure that instead of color, you can see this cherished pattern. Checker.
How to properly store transparent images
We are all used to such a photo format as jpeg. Some people are not even aware of the existence of others. However, he does not understand what transparency is. In order to download and store the "correct" photos on your computer, you will need to understand and remember the new format - png.
You see, in addition to the checkers, in Google you can almost always see this combination of letters along with the necessary pictures.
Then select the desired file type, png and you're done. It is available in every version. If you don't see it, look harder. Nothing without him. Trust me.
Why was it necessary to come up with a different format? The thing is that the popular jpeg does not understand what transparency is. He changes it to the usual white.
How to get rid of the background: a simple and fairly quick way without unnecessary troubles
On my blog, you can find an article in which I show 4 tools and a video in which you can find 3 ways to get rid of the background in the picture (). You can read it if you are interested. Now I would like to show you one more trick, because I think that without it the article would not be complete. You never know, someone does not want to climb my blog. And here everything is in one place.
So let's open the picture.
Find the Background Eraser tool. If you cannot find it, then hold the mouse for a few seconds with the left button pressed on the key of a regular eraser. The desired tool will open. You can add it by clicking on it.
You can increase the diameter of the eraser to make it easier to erase.
Now play around with the unnecessary elements in the picture. You will see how the checker begins to appear, and the color disappears!
I hope that after you finish, you will not have a question in what format to save the processed drawing. PNG of course.
This erasing method cannot be called the best and incredibly convenient. Therefore, I recommend that you still pay attention to my previous article, which is completely devoted to this topic.
And if you are interested in working in Photoshop, then I advise you to start making money on it! There is a demand. You can easily try, process pictures, and do a lot of interesting things. Believe me, this is really necessary. You can make sure by checking out a few freelance websites.
Think you can't do it or are you too old for this shit? Not enough time? Believe me, these are all ridiculous excuses. I am a lawyer and I earn enough, but… do you have a hobby, a favorite hobby? You live full life? Are you really not bored?
Whatever you know and whatever you are interested in. The Internet opens up a lot of new possibilities. Let change into your life. If money doesn't interest you, that's even better. This gives your project more chances to become expensive, cool and successful. All famous people don't work for profit, they work because they love what they do. Few of them call it "work".
Gone are the days when people spent most of their time at the computer or TV. Now everyone is developing, improving some of their skills and sharing with people what they know. In fact, it has always been like this, only the scale has increased.
By the way, not so long ago I read the secrets of the longevity of the Caucasian highlanders. One of the principles is that the younger generation constantly goes to them to consult on some important issue. Old people feel needed, and therefore do not experience any negative emotions about old age. In the Caucasus, do not be afraid to become old.
By the way, a positive attitude is another of their secrets. The elders argue that no one wants to communicate with angry, irritated and boring people who do not have interesting hobbies, and therefore, such a lifestyle is extremely unprofitable, especially in old age.
Do something new. If you like Photoshop, pay attention to the course of Zinaida Lukyanova - “ Photoshop from scratch and master it to perfection. Very quickly you will have a profitable hobby. Not so passionate about design? Pay attention to that, and create your own projects.
If you liked this article, and I at least a little interested you, subscribe to the mailing list. Maybe not now, but give yourself a chance to do something new. I will send you my publications on how you can make money on the Internet.
Perhaps one of them will inspire you to something new and yet unknown. You will understand that it is interesting and you will want to try it yourself, and then ... who knows what will happen next?
Will the hobby turn into something more or will you just show the result of your work to your friends in order to get their praise and admiration? Unlike many, you will get up from the couch and do something that will take you beyond the usual. You will try to change your life. This is very commendable.
I sincerely wish you success in your endeavors and hope that this meeting of ours will not be the last.